1. Field of the Invention
The present invention relates to an electromagnetic relay, particularly, an electromagnetic relay for high voltage having a shading coil.
2. Description of the Related Art
There is conventionally a structure in which the height size of a device is limited from the request of making the device compact as the electromagnetic relay (e.g., see patent literature 1).
[Patent literature 1]
JP-A-11-16472
Namely, in this electromagnetic relay, an electromagnet block rises on one side of the upper face of abase, and a contact mechanism is arranged on the other side of this base upper face. A movable iron piece is rotated on the basis of magnetizing and demagnetizing forces of the above electromagnet block, and the contact mechanism is operated through a card.
However, when the shading coil was intended to be mounted to a magnetic pole portion of an iron core of the above electromagnetic relay, it was inevitable to raise the height size of the entire electromagnet device. On the other hand, when the height size was limited from the request of the compactness of the device, it was necessary to correspondingly shorten the drum portion of a spool by the height size of the shading coil. As this result, the winding number of the coil able to be wound around the above drum portion is reduced so that no predetermined desirable driving force is obtained. Accordingly, opening and closing characteristics are reduced and an adjustable allowance range is narrowed as the opening and closing characteristics are reduced. Therefore, problems exist in that high accuracy of parts and assembly precision are required and productivity is reduced.
Further, when the above electromagnetic relay is intended to cope with the high voltage, it is necessary to secure a predetermined insulating distance between a drawing start portion of the coil bound and drawn out of a coil terminal and a winding termination portion of the coil completely wound. Therefore, the drawing start portion of the coil is drawn out of a coil drawing-out groove formed along the outer circumferential edge portion of a flange portion. However, when the coil drawing-out groove is intended to be formed in the above flange portion, the thickness of the flange portion is increased and the entire height size is increased. Accordingly, when the height size of the electromagnetic relay is limited, it is necessary to shorten the spool and problems similar to those in the above case are caused.